In Situ Construction of Gradient Oxygen Release Buffer and Interface Cation Self‐Accelerator Stabilizing High‐Voltage Ni‐Rich Cathode

Abstract

Ni‐rich cathodes with superior energy densities have spurred extensive attention for lithium‐ion batteries (LIBs), whereas their commercialization is hampered by structural degradation, thermal runaway, and dramatic capacity fading. Herein, boron (B) with high binding energy to oxygen (O) is gradiently incorporated into each primary particle and piezoelectric Li2B4O7 (LBO) is homogeneously deposited on the secondary particles of polycrystalline LiNi0.8Co0.1Mn0.1O2 (NCM811) surface through a facile in situ construction strategy, intending to synchronously enhance electrochemical stabilities and Li+ kinetics upon cycling. Particularly, the as‐obtained LBO modified NCM811 cathode exhibits an excellent capacity retention (88.9% after 300 cycles, 1 C) and rate performance (112.2 mAh g−1, 10 C) with Li metal anode, the NCM811‐LBO/Li4Ti5O12 full cell achieves a capacity retention of 92.6% after 1000 cycles (0.5 C). Intensive explorations in theoretical calculation, multi‐scale in/ex situ characterization and finite element analysis ascertain that the improvement mechanism of LBO modification can be attributed to the synergistic contributions of rational designed O release buffer and interface cation self‐accelerator. This study provides a facile and practical method to prevent structural degradation and thermal runaway for high‐energy LIBs.

Improving the long-term electrochemical performances of Li-rich cathode material by encapsulating a three-in-one nanolayer

“…49,50 In addition, the B 3+ ions doped at the tetrahedral sites can block the migration path of TM ions upon electrochemical cycling, thus inhibiting the irreversible phase transition and enhancing the electrochemical stability of Li-rich materials. 51,52…”

Understanding the Synthesis Kinetics of Single‐Crystal Co‐Free Ni‐Rich Cathodes

“…In situ XRD was carried out to explore the influence of molten-salt synthesis on the phase evolution and structural changes during the charge-discharge process in Fig- ure 4. [30][31][32][33][34][35][36][37][38][39] The 3D contour plots of (003), ( 101), ( 104) and (018)/(110) diffraction peaks of the two materials exhibit an obvious charge-dependent displacement state. The results demonstrate that the two materials undergo a similar structural evolution process, but the changes of c-axis parameters are obviously different.…”

Field‐assisted electrocatalysts spark sulfur redox kinetics: From fundamentals to applications

“…[ 198 ] Nevertheless, the concomitant stress evolution might allow us to turn waste into treasure without additional costs if coupled with piezoelectric electrocatalysts. The merits of piezoelectric coating layers on Li + diffusion at the cathode‐electrolyte interface have been verified by Bai et al, [ 66,199–202 ] which is appealing to dig in‐depth insight into the interface coupling strategy between mechanical and EF to purposefully regulate the interfacial kinetics of negatively charged polysulfides and positively charged Li + . Several representatives of piezoelectric semiconductors, such as ZnO, MoS 2 , and MoSe 2 , occupy the top position of potential piezoelectric electrocatalysts.…”